Accused Boston Marathon bomber Dzhokhar Tsarnaev has been charged with using a weapon of mass destruction against persons and in connection with the blasts that killed three and wounded at least 176 last week.

The charges were unsealed hours after Tsarnaev had his initial court appearance from his hospital bed.

The case being built against the 19-year-old college student includes one count of using a weapon of mass destruction resulting in death, and one count of malicious destruction of property. The Justice Department released a statement indicating that the charges could carry the death penalty or life in prison.

“Although our investigation is ongoing, today's charges bring a successful end to a tragic week for the city of Boston, and for our country,” Attorney General Eric Holder said in the statement. “We will hold those who are responsible for these heinous acts accountable to the fullest extent of the law.”

Law enforcement sources say Dzhokhar Tsarnaev, 19, was arraigned at his hospital bed, which was first reported byABC News affiliate WCVB.

Tsarnaev was awake and responding sporadically in writing to questions Sunday night. They are asking about any possible cell members and other unexploded bombs. There have been no additional details yet on his answers.

Tsarnaev is being treated at Beth Israel Deaconess Medical Center in Boston, where he is listed in serious but stable condition, with wounds to the neck and throat area, according to sources.

The arraignment occurred as Tsarnaev's parents have been defending their sons' innocence in interviews in Russia. The mother of the bombing suspects told ABC News she spoke to her eldest son minutes before a violent standoff with police in the streets of Watertown, Massachsuetts.

Tamerlan Tsarnaev, 26, called his mother early Friday morning, alerting her that police were following him and his younger brother and that there had been a shooting.

“'The police, they have started shooting at us, they are chasing us,'” Zubeidat Tsarnaeva told ABC News in a telephone interview.

The conversation ended when Tsarnaev said, “'Mama, I love you,'” his mother said.

Tsarnaeva got frightened and started to cry and shout. He told her Dzhokhar Tsarnaev, 19, was with him before the line cut off.